Hankook v4 tires

Hey folks. Quick question about these tires. I put about 5k miles on them myself and when I bought the car they probably had 5 or 6k on them. Anyway I hit a pothole and ended up with a huge knot / bubble on the sidewall of the front passenger. So i got two new front tires and was on my way to recovery. I decided to stash the front drivers side for a full spare. A week went by I and noticed that there was a bubble in the sidewall of the back passenger about half the size of the other one. Well long story short, I went today to grab the spare so I could swap it out and low and behold, another bubble in the sidewall. What is up with this? That makes three of the Hankook v4 that I've gone through in 4 months!

Is anyone experiencing anything similar?

I got a response from a Hankook rep today regarding my issue. Here's it is:

Thanks for the questions/comments.

Coincidentally, I own a 2006 Subaru Legacy 2.5GT Limited. Two years ago I installed a set of the same V4es tires (size 215/45R17). I am fortunate enough to say that I have been bubble-free for about 50k miles – which is a feat considering the terrible Northern New Jersey roadways.

As you have indicated, sidewall bubbles/bulges are almost always a result of impact damage (with potholes being the most likely culprit). Basically the impact is strong enough to break the radial casing cords, allowing the bubble to form in the sidewall. The V4es does not have any history of higher susceptibility to impact damage. I feel that your situation can be chalked up to poor road quality or simply bad luck. With any low profile tire it is important to vigilantly evade potholes to avoid experiencing these bubbles.

The Ventus V4es comes with a Road Hazard warranty that covers any non-repairable road hazards for the first 25% of tread depth (see website for details).

Also, I recommend taking a closer look at the Subaru owner’s manual. To my knowledge, Subaru recommends replacement of tires in sets of 4 due to the AWD configuration. When you have tires of varying overall diameters, excessive wear can be forced onto the drivetrain (limited slip differential) resulting in damage.